A typical touch screen employs a sheet of glass with a conductive coating, such as indium tin oxide, with four corner terminal connections. The touch screen may be configured as a capacitive or resistive touch screen, with a pattern of electrodes made of conductive material. A finger, stylus, or conductive top sheet can draw or inject current at the point of contact. The current can then distribute to the touch panel terminals in a proportionate manner relative to the location of the point of contact.
Touch detection accuracy of the touch screen can change over time due to a number of system and environmental reasons, such as wear during extended use. Monitoring, testing, and servicing of touch screen systems has conventionally involved manual evaluation of a suspect system by an on-site technician. Such conventional evaluation and repair approaches are both costly and time inefficient.